The present invention relates generally to bar code scanners and, more specifically, to scanning both small and large bar codes with the same scanner.
Conventional bar codes have varying width bars and spaces suitably printed on a label. The bar code may take any conventional form in one or more dimensions, and includes, for example, the typical one-dimensional UPC form. The UPC symbology is based on a specification enacted by the Uniform Product Code Council, Inc. of Dayton Ohio. The typical UPC bar code includes a series or sequence of alternating dark bars and light spaces of varying widths. The bars and spaces are arranged in groups representing individual characters. The bar code starts with a left margin character and ends with a right margin character, and has a center reference character as well, with the characters provided there between representing any desired data.
The minimum width of either a bar or space in the UPC symbology is defined as a single module, which represents a unit width. The width of a single character coded using the UPC symbology is seven (7) modules. A seven module UPC character has two bar and two space elements which have varying widths to differentiate between the respective characters.
There are many types of bar code symbologies (encoding schemes). For example, there are a number of different one-dimensional bar code symbologies. These symbologies include UPCIEAN, Code 39, Code 128, Codabar and Interleaved 2 of 5. There are also 2 dimensional bar code symbologies.
Bar code scanners utilize a laser beam in order to illuminate a bar code, during the scanning process. The light reflected from the pattern of bars and spaces is analyzed in order to read the bar code. For the bar code to be read clearly the laser beam must be focused at or adjacent the bar code. Laser beams used to illuminate bar codes have a limited depth of field over which they are focused. Typically, the beam will focus several inches beyond the scanner window in order to maximize the portion of its usable range that is in the scan zone.
However, this results in the laser spot at the scan window being large and unfocused. When the operator encounters a small (demagnified) bar code he or she typically places the bar code on the window, where unfortunately it is even less likely to be read by the scanner.
It is an object of the present invention to produce a bar code scanner, which obviates the problems discussed above.
According to a first aspect of the present invention there is provided a bar code scanner having a housing including a surface having a transparent scanning window; and optical components including a spinner located within the housing and arranged to produce both a first set of scan lines focused outside of the housing and remote from the scanning window; and a second set of scan lines focused outside of the housing and adjacent the scanning window.
According to a second aspect of the present invention there is provided a method of scanning a bar code, utilizing a bar code scanner having a housing including a surface having a transparent scanning window; and optical components including a spinner located within the housing and arranged to produce both a first set of scan lines focused outside of the housing and remote from the scanning window; and a second set of scan lines focused outside of the housing and adjacent the scanning window, including the steps of placing a bar code to be read in either a first position where said first set of scan lines are focused or in a second position wherein said second set of scan lines are focused.